Salivary pellicle composition and multispecies biofilm developed on titanium nitrided by cold plasma

Objective: The aim of this study was to evaluate the composition of the salivary pellicle (SP) and multispecies biofilm developed on titanium nitrided by cold plasma. Methods: Titanium discs were allocated into a control group (Ti) and an experimental group (TiN - titanium-nitrided by cold plasma). The disc surface topography was characterized by scanning electron microscopy (SEM) and atomic force microscopy (AFM). The chemical composition of the disc surface was determined by X-ray photoelectron spectroscopy (XPS). Stimulated, clarified, and filtered saliva was used to form pellicles on the discs. Proteome analysis of the adsorbed SP proteins was performed by liquid chromatography-mass spectrometry (LC-MS). The surface free energy (SFE) was evaluated before and after SP formation. A multispecies biofilm composed of Actinomyces naeslundii, Streptococcus oralis, Streptococcus mutans, Fusobacterium nucleatum, Veillonella dispar, and Candida albicans was developed on the SP-coated discs. Viable microorganism counts were determined. The biomass and average thickness of biofilms were analyzed by confocal laser-scanning microscopy (CLSM) with COMSTAT software. The biofilm organization was visualized by SEM. Results: The surface topography was similar in both groups. The SFE of the TiN group did not differ from that of the Ti group (p > 0.05), although the adsorption of pellicle proteins increased the SFE in both pellicle-coated groups (p < 0.001). Different proteins were identified on the Ti and TiN surfaces. The amount of biofilm was similar for both groups (p = 0.416), but the counts of F. nucleatum and S. oralis were higher in the TiN group (p < 0.001). Similar biofilms were characterized by the COMSTAT data, CLSM images, and SEM images. Conclusion: The titanium nitrided by cold plasma exhibited differences in SP composition and multispecies microbial biofilm population compared to the control titanium surface. (C) 2014 Elsevier Ltd. All rights reserved.